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/* dup2.c
The Unix dup2 function, for systems which only have dup.
Copyright (C) 1985, 1986, 1987, 1988, 1990 Free Software Foundation, Inc.
This file is part of the Taylor UUCP package.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
The author of the program may be contacted at ian@airs.com or
c/o Cygnus Support, 48 Grove Street, Somerville, MA 02144.
*/
#include "uucp.h"
#include "sysdep.h"
#include <errno.h>
#if HAVE_FCNTL_H
#include <fcntl.h>
#else
#if HAVE_SYS_FILE_H
#include <sys/file.h>
#endif
#endif
/* I basically took this from the emacs 18.57 distribution, although I
cleaned it up a bit and made it POSIX compliant. */
int
dup2 (oold, onew)
int oold;
int onew;
{
if (oold == onew)
return onew;
(void) close (onew);
#ifdef F_DUPFD
return fcntl (oold, F_DUPFD, onew);
#else
{
int onext, oret, isave;
onext = dup (oold);
if (onext == onew)
return onext;
if (onext < 0)
return -1;
oret = dup2 (oold, onew);
isave = errno;
(void) close (onext);
errno = isave;
return oret;
}
#endif
}
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